Japanese Journal of Clinical Oncology Advance Access published online on June 23, 2007
Japanese Journal of Clinical Oncology, doi:10.1093/jjco/hym048
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© 2007 Foundation for Promotion of Cancer Research
Breast Cancer in First-degree Relatives and Risk of Lung Cancer: Assessment of the Existence of GeneSex Interactions
1 Epidemiology and Prevention Division, Research Center for Cancer Prevention and Screening, National Cancer Center, Tokyo
2 Thoracic Oncology Division, Research Center for Innovative Oncology, National Cancer Center Hospital East
3 Psycho-Oncology Division, Research Center for Innovative Oncology, National Cancer Center Hospital East, Kashiwa, Chiba, Japan
For reprints and all correspondence: Motoki Iwasaki, Epidemiology and Prevention Division, Research Center for Cancer Prevention and Screening, National Cancer Center, 5-1-1 Tsukiji, Chuo-ku, Tokyo, 104-0045, Japan. E-mail: moiwasak{at}gan2.res.ncc.go.jp
Received November 22, 2006; accepted January 29, 2007
Background: Previous studies have shown the sex differences in lung cancer and the associations between estrogen-related genes and non-small cell lung cancer. In the present study, we assumed the existence of shared candidate genes that are common in lung and breast cancers, and examined whether women with a family history of breast cancer are at increased risk of lung cancer compared with men, especially adenocarcinoma, in a case-only study.
Methods: This case-only study was conducted based on the Lung Cancer Database Project at the National Cancer Center Hospital East. A total of 1566 patients with newly diagnosed primary lung cancer were consecutively recruited between 1999 and 2003. Information on their family history of cancer and smoking habit was obtained from a self-administered questionnaire. To assess an interactions between two factors, odds ratios for interaction (ORis) and 95% confidence intervals (CIs) were calculated by case-only contingency table.
Results: A statistically significant ORi was observed between a family history of breast cancer in first-degree relatives (parent and siblings, not including children) and the sex of a patient (ORi: 2.22, 95% CI: 1.024.81). A stratified analysis by histologic subtypes showed a statistically significant ORi only for adenocarcinoma (ORi: 3.27, 95% CI: 1.198.98). No other family history of cancer, such as stomach, colon and lung cancer, showed a statistically significant ORi.
Conclusion: This study suggests the possibility of genesex interaction in lung cancer.
Key Words: lung cancer breast cancer shared candidate genes gene sex interaction